Adam Rogers writes: Imagine an election—A close one. You’re undecided. So you type the name of one of the candidates into your search engine of choice. (Actually, let’s not be coy here. In most of the world, one search engine dominates; in Europe and North America, it’s Google.) And Google coughs up, in fractions of a second, articles and facts about that candidate. Great! Now you are an informed voter, right? But a study published this week says that the order of those results, the ranking of positive or negative stories on the screen, can have an enormous influence on the way you vote. And if the election is close enough, the effect could be profound enough to change the outcome.

In other words: Google’s ranking algorithm for search results could accidentally steal the presidency. “We estimate, based on win margins in national elections around the world,” says Robert Epstein, a psychologist at the American Institute for Behavioral Research and Technology and one of the study’s authors, “that Google could determine the outcome of upwards of 25 percent of all national elections.”

Epstein’s paper combines a few years’ worth of experiments in which Epstein and his colleague Ronald Robertson gave people access to information about the race for prime minister in Australia in 2010, two years prior, and then let the mock-voters learn about the candidates via a simulated search engine that displayed real articles.

One group saw positive articles about one candidate first; the other saw positive articles about the other candidate. (A control group saw a random assortment.) The result: Whichever side people saw the positive results for, they were more likely to vote for—by more than 48 percent. The team calls that number the “vote manipulation power,” or VMP. The effect held—strengthened, even—when the researchers swapped in a single negative story into the number-four and number-three spots. Apparently it made the results seem even more neutral and therefore more trustworthy.

But of course that was all artificial—in the lab. So the researchers packed up and went to India in advance of the 2014 Lok Sabha elections, a national campaign with 800 million eligible voters. (Eventually 430 million people voted over the weeks of the actual election.) “I thought this time we’d be lucky if we got 2 or 3 percent, and my gut said we’re gonna get nothing,” Epstein says, “because this is an intense, intense election environment.” Voters get exposed, heavily, to lots of other information besides a mock search engine result.

The team 2,150 found undecided voters and performed a version of the same experiment. And again, VMP was off the charts. Even taking into account some sloppiness in the data-gathering and a tougher time assessing articles for their positive or negative valence, they got an overall VMP of 24 percent….(read more)